The ornamental design for a tire tread, as shown and described.
FIG. 1 is a front elevational view of a tire tread showing my new design on the face of a tire; and,
FIG. 2 is a perspective view thereof.
The broken lines in both Figures are for illustrative purposes only, showing the relation of the claimed tire tread to the remaining portions of the tire, which itself forms no part of the claimed design. The claimed design is only visible on the exterior face of the tire and consists of a repeating pattern which appears identical no matter which section of the tire face is viewed.